| Author |
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Rick_a
| | Posted on Thursday, June 30, 2005 - 12:51 pm: | 
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That's some awesome info. I have wondered about the compatibility of the 51mm float bowl. Good to know. I still don't regret the purchase of the Mikuni, though.
My bike had a Thunderslide equipped CV. I never could get it to work quite right. I ended up putting the stock slide back in with the drilled port and kept the Dynojet main jet, jet needle, and needle jet in there. I used the spring that came in the standard Dynojet kit. I also removed the accelerator pump completely. That's the best I ever got that carb to work. |
Henrik
| | Posted on Thursday, June 30, 2005 - 01:06 pm: |
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Thanks Wes. That's fantastic information. It's been copied and pasted into my Buell info archives.
I have a Mikuni, new in box, that I've been wanting to put on the S2, when I at some point do some motor work. However, my concern has been altitude changes etc., since the S2 is my main touring mount, and I mostly head to the Blue Ridge Mountains for MC trips.
A better performing Keihin, able to keep up with some motor mods would be ideal.
Thanks again. Great stuff.
Henrik |
Tramp
| | Posted on Thursday, June 30, 2005 - 01:29 pm: |
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before you jump to any new dogmae, please try adjusting your mixture screw out 3-4 turns from closed, and start with a 48 pilot and a 185 or 190 main.
i've set up zillions of these kehins on buells, and that's the mean jet ratio i've come up with.
don't get too worked up over various accel. pumps, etc., the correct jetting will do wonders in most stock keihins, when the mixture screw is turned out a bit more than is often proscribed.... |
Bomber
| | Posted on Thursday, June 30, 2005 - 01:44 pm: |
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Tramperoo -- right you are, this sinks into a religious argument for many -- me, I've had really good luck with Racer's suggestions -- adjusted mixture for max idle speed (lil thumbscreww thingie held a bit with that)
I thiunk many folks read- "set screw 1.5-2.5 turns out for a baseline," set it there, and don't experiemtn --
anywho, I imagine both will work -- I know Racer's does, you know your's does, life's pretty darned good, eh? (practicing for my ride through the UP this summer) |
Henrik
| | Posted on Thursday, June 30, 2005 - 06:08 pm: |
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Speaking from vague memory (it's getting there  ) - isn't there something about more than a certain # of turns out on the idle mixture screw should translate into a step up in pilot jets?
Btw. what fun are dogmae (plural ?  ) if you don't just jump in 
Henrik |
Rick_a
| | Posted on Thursday, June 30, 2005 - 06:31 pm: |
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It's easy to get the A/F ratio where you want it. Getting the feel and response you want out of a CV is the hard part. |
Krassh
| | Posted on Thursday, June 30, 2005 - 10:11 pm: |
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I don't seem to have any problems with my Mikuni on my Electra Glide with going from the valley floor up to 4700+ feet where I live. What problems do the Mikuni's have with altitude? |
Captainkirk
| | Posted on Thursday, June 30, 2005 - 11:46 pm: |
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They don't compensate automatically. |
Tramp
| | Posted on Friday, July 01, 2005 - 03:02 am: |
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and what's the vertical travel? (ie, what's the elevation of the "valley floor"? 4700' is not too high. in the rockies and the sierra you'll be over double that.
now, staring at the Sf bay, riding 4 hr.s up to tahoe, you'll have an easy 9000 feet of evrtical travel in 4 hr.s
a li'l difference, ne'est ce pas? |
Rick_a
| | Posted on Friday, July 01, 2005 - 08:31 am: |
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A CV still only compensates for the midrange and to a limited degree. It's still a compromise even going from the winter to summer months, let alone the altitude you're at. |
Bomber
| | Posted on Friday, July 01, 2005 - 08:51 am: |
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H -- yes, I remember the same rule of thumb -- I believe it's sumpin like 3 turns out or more = next higher jet, but that data is WAY in the back of the stacks, and I don't go back there often (too scary!)
I also never tried to verify that particular piece of wisdom (dogma), as my carb is working nicely -- I figured I'd stop fiddlin with it while I was ahead ;-}
given Tramp's suggestion above, I kinda doubt that rule of thumb's accuracy -- likely has some applicability to the realy world, but not scripture, if I may continue the religious term usage |
Tramp
| | Posted on Friday, July 01, 2005 - 10:03 am: |
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"A CV still only compensates for the midrange and to a limited degree. It's still a compromise even going from the winter to summer months, let alone the altitude you're at." -Rick_a.
????????????????????? I haven't jerked around with my CV in years, and it runs splendidly in -20o F winter weather, as well as this 90o F summer... It's ridden up over the Donner Summit in california and Loveland Pas in Colorado, and I live at about 400' above sea level right now, with excellent reponse.
What other gleaming examples of wide-range carbs, exactly, IS it a compromise for? |
Rick_a
| | Posted on Friday, July 01, 2005 - 01:43 pm: |
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Try it on the dyno in both conditions. There is a difference. |
Rick_a
| | Posted on Friday, July 01, 2005 - 01:44 pm: |
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No carburetor is truly self-compensating. That's what EFI is for. |
Tramp
| | Posted on Friday, July 01, 2005 - 02:14 pm: |
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yeah- um.... rick- when i decide to do my riding on 'dynos' i'll get right on that.
for now, riding the highways and backroads of america,from coast-to-coast year-round, my Keihin CV carb is doing great with no diddling whatsoever.
guess i'm too ignorant to realize that the dyno could debunk THAT myth |
Tramp
| | Posted on Friday, July 01, 2005 - 02:18 pm: |
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"No carburetor is truly self-compensating. That's what EFI is for." -Rick_a
ahhh, yes- I believe "compensation" may just be at the heart of your Buelling issues
unless you're racing (and making some benjamins at it)
Skip the dyno, take two loooooong twisty rides and call me in the morning |
Ezblast
| | Posted on Friday, July 01, 2005 - 04:08 pm: |
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I thought this thread was about getting better response out of your CV carb to match the Mikuni's ability.
GT - JBOTDS! EZ |
Tramp
| | Posted on Friday, July 01, 2005 - 04:49 pm: |
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nope-
this thread was about putting a CV on in place of FI. |
Ezblast
| | Posted on Friday, July 01, 2005 - 05:13 pm: |
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True to a point - but then it evolved into CV vs. Mikuni, then into bettering the CV performance - that is what I and others here where interested in.
GT - JBOTDS! EZ |
Rick_a
| | Posted on Friday, July 01, 2005 - 06:04 pm: |
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Not at all. Everything could use improvement. I'm not satisfied with an 84hp bike. I'd like 100. I'm quite satisfied with myself at the moment, though, thank you. Tuning is what made my stock 76hp S1 an 84 hp bike. I'm just giving my opinion that no matter what I did with the CV I still wasn't fully satisfied with it.
You like it relatively stock and the CV40 works for you. Good for you. What's the point of buttin' heads about it Tramp? Are the silly personal comments necessary? I think not. |
Garrett1998s1
| | Posted on Friday, July 01, 2005 - 06:18 pm: |
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Can someone tell me how much difference there is in a cv that came off a 92 sportster and the one off my 98 S1W? |
Tramp
| | Posted on Friday, July 01, 2005 - 07:33 pm: |
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jeepers, fellers- i wuz juss joshin'.....golly.
(don't take things so seriously, it's only a motor-sickle....jeepers) |
Phillyblast
| | Posted on Friday, July 01, 2005 - 09:12 pm: |
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garrett -
about 6 years I think. |
Garrett1998s1
| | Posted on Friday, July 01, 2005 - 10:06 pm: |
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lol well with all the info that I got about the 2004 and newer sportster cv carb was hoping to get some info on an older one I was lookin at buying. |
Tramp
| | Posted on Saturday, July 02, 2005 - 12:33 am: |
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Oh, man. It's just a keihin cv. pay under $30 and slap it on and GO |
Rick_a
| | Posted on Saturday, July 02, 2005 - 11:24 am: |
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Mainly the jets, needle, and mixture screw setting will be different. '91 and prior have a float bowl with an overflow instead of the drain. |
Garrett1998s1
| | Posted on Saturday, July 02, 2005 - 04:22 pm: |
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thanks |
Racerx1
| | Posted on Sunday, July 03, 2005 - 01:47 pm: |
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Sorry Garrett....my knowledge base only goes back to about 1998! I'll dig around and see if i can find anything out though.
I hope nobody got the impression I was dissing Mikuni....I definitely was not. Very fine carburetor that I honestly don't have a lot of experience with. Just sharing my Keihin CV experience which happened to work pretty well for me. I have had a lot of luck with the Keihin CV, particularly the 44mm on drag and road race bikes. Having said that however, I picked up a 45 mik to try on the drag bike. It flowed the most on a flow bench through a sporty screaming eagle manifold so it looks like there is some potential there...Half the fun is experimenting with this stuff!
As far as carbs being self compensating, I'm not going to get into an argument on that one as all carbs obey the laws of physics and bernoulli's theorm, and to a varying extent can 'self compensate' to varying degree for any of the variables in the equation (pressure, velocity, density, etc...). A CV (Constant Velocity)carb tends to make the velocity variable into a constant, so it could be successfully argued it has a bit more range of authority than a flat slide. Whatever floats your fuel float. |
Rick_a
| | Posted on Wednesday, July 06, 2005 - 08:25 am: |
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Another thing I forgot...the '91 and prior CV's use a hollow float while the '92 and later use a solid composite float (no leaks).
If you can find a first year CV ('88) it has no accelerator pump. |
Tramp
| | Posted on Wednesday, July 06, 2005 - 10:42 am: |
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Nice point, Rick- actually makes a nice difference! |
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